#include "il2cpp-config.h"
#include <cassert>
#include <ctype.h>
#include "icalls/mscorlib/System/Convert.h"
#include "il2cpp-api.h"
#include "class-internals.h"
#include "object-internals.h"
#include "vm/Array.h"
#include "vm/Image.h"
#include "vm/Exception.h"

namespace il2cpp
{
namespace icalls
{
namespace mscorlib
{
namespace System
{

Il2CppArray* Convert::InternalFromBase64String (Il2CppString* str, bool allowWhitespaceOnly)
{
	return Base64ToByteArray(str->chars, str->length, allowWhitespaceOnly);
}

Il2CppArray* Convert::InternalFromBase64CharArray (Il2CppArray* chars, int32_t offset, int32_t length)
{
	return Base64ToByteArray(il2cpp_array_addr(chars, Il2CppChar, offset), length, false);
}

Il2CppArray* Convert::Base64ToByteArray (Il2CppChar* start, int length, bool allowWhitespaceOnly)
{
	int ignored;
	int i;
	Il2CppChar c;
	Il2CppChar last, prev_last, prev2_last;
	int olength;
	Il2CppArray *result;
	unsigned char *res_ptr;
	int a [4], b [4];

	const static unsigned char dbase64 [] =
	{
		128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128,
		128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128,
		128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 62, 128, 128, 128, 63,
		52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 128, 128, 128, 0, 128, 128,
		128, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
		15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 128, 128, 128, 128, 128,
		128, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
		41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51
	};

	ignored = 0;
	last = prev_last = 0, prev2_last = 0;
	for (i = 0; i < length; i++)
	{
		c = start [i];
		if (c >= sizeof (dbase64))
		{
			// The content of this exception message matches Mono, but differs from .Net.
			il2cpp_raise_exception (vm::Exception::GetFormatException("Invalid character found."));
		}
		else if (isspace (c))
		{
			ignored++;
		}
		else
		{
			prev2_last = prev_last;
			prev_last = last;
			last = c;
		}
	}

	olength = length - ignored;

	if (allowWhitespaceOnly && olength == 0)
		return vm::Array::New(il2cpp_defaults.byte_class, 0);

	if ((olength & 3) != 0 || olength <= 0)
	{
		// The content of this exception message matches Mono, but differs from .Net.
		il2cpp_raise_exception (vm::Exception::GetFormatException("Invalid length."));
	}

	if (prev2_last == '=')
	{
		// The content of this exception message matches Mono, but differs from .Net.
		il2cpp_raise_exception (vm::Exception::GetFormatException("Invalid format."));
	}

	olength = (olength * 3) / 4;
	if (last == '=')
		olength--;

	if (prev_last == '=')
		olength--;

	result = vm::Array::New(il2cpp_defaults.byte_class, olength);
	res_ptr = il2cpp_array_addr (result, unsigned char, 0);
	for (i = 0; i < length; )
	{
		int k;

		for (k = 0; k < 4 && i < length;)
		{
			c = start [i++];
			if (isspace (c))
				continue;

			a [k] = (unsigned char) c;
			if (((b [k] = dbase64 [c]) & 0x80) != 0)
			{
				// The content of this exception message matches Mono, but differs from .Net.
				il2cpp_raise_exception (vm::Exception::GetFormatException("Invalid character found."));
			}
			k++;
		}

		*res_ptr++ = (b [0] << 2) | (b [1] >> 4);
		if (a [2] != '=')
			*res_ptr++ = (b [1] << 4) | (b [2] >> 2);
		if (a [3] != '=')
			*res_ptr++ = (b [2] << 6) | b [3];

		while (i < length && isspace (start [i]))
			i++;
	}

	return result;
}

} /* namespace System */
} /* namespace mscorlib */
} /* namespace icalls */
} /* namespace il2cpp */
